Social media company Instagram pulled photos by U.S. photographer Imogen Cunningham promoting an exhibit at Boston's Museum of Fine Arts, saying they violated decency standards, even as parent company Facebook Inc faces criticism for users' live videos of murder.

Visitors look at the exhibit 'Imogen Cunningham: In Focus' at the Museum of Fine Arts, Boston, in Boston, Massachusetts, U.S., April 26, 2017.

At issue were posts of 1920s black-and-white photos by Cunningham depicting close-ups of a naked women's torso, which turn the body into an almost abstract shape, and a 1974 photo of Cunningham at the age of 91 gazing around a tree trunk at one of her favorite models, who is shown nude.

"This startled us," Karen Haas, the museum's curator of photographs, said in a phone interview on Wednesday. "Here is this artist who has been dead for a long time, who had this seven-decade career, who fought the fight to have photography considered as fine art along with her contemporaries so long ago, and we felt this fight was long since over."

The 140-year-old art museum is one of the largest in the United States.

Instagram took down two of Cunningham's images: "Triangles," depicting a close-up of a woman's breast, and "Sunbath (Alta on the Beach)." It also removed Judy Dater's 1974 "Imogen and Twinka."

This comes as social media companies are encountering criticism after users posted live videos of violence. This week a Thai man broadcast himself killing his 11-month-old daughter, and earlier this month a man posted a video of himself murdering an elderly man in Cleveland. Both videos were posted to Facebook.

Facebook officials did not respond to a request for comment on Wednesday.

Instagram's online guidelines say the service does not allow photos depicting nudity, even if they are "artistic or creative in nature," and that it prohibits "some photos of female nipples." The site says it does allow photos of post-mastectomy scarring and women breastfeeding, as well as of paintings and sculptures depicting nudity.

The Boston Globe first reported the controversy.

Cunningham, who lived from 1883 through 1976 and is best work for her 1920s close-ups of flowers, is regarded as a pioneer in American photography.

Like other museums, the MFA regards Instagram and other social media platforms as a way to attract visitors and expand their educational reach, said spokeswoman Karen Franscona.

Source: Reuters